The bone-implant interface: a dynamic surface.

This study quantifies and compares bone formation on and around roughened titanium implants with roughened cobalt chromium, polished solid implants, and titanium fibermetal implants. Cylindrical rods were implanted into the medullary canal of the distal femur of rabbits. The bone-implant interface was studied 3, 6, and 12 weeks after surgery using histomorphometric methods. Roughened surface implants demonstrated significantly more bone directly apposed to the surfaces when compared to the polished or fiber/metal implants at 6 and 12 weeks after surgery. New bone formation and remodeling of bone occurred directly on roughened surfaces as late as 12 weeks after implantation, but not on the unroughened implants. These results suggest that roughening of the surfaces of both titanium and cobalt chromium implants can enhance osseointegration and may be useful clinically for the fixation of prosthetic components.